Sealing Gasket

This application is a national stage entry under 35 U.S.C. § 371 of International Application No. PCT/GB2023/052232, filed Aug. 30, 2023, which claims the benefit of GB Application No. 2213812.7, filed Sep. 22, 2022, and GB Application No. 2308566.5, filed Jun. 8, 2023, the entire contents of each of which are incorporated herein by reference.

The field of the disclosure relates to a sealing gasket for a vacuum pump, and a vacuum pump.

Rotating machines, such as compressors or pumps, may be carefully designed and manufactured in order for the moving parts to cooperate with each other accurately. Providing effective seals to seal the machine tends to be problematic, particularly when fluid flow is encouraged by a pressure difference between the machine and ambient environment, such as in a vacuum pump. It is desired to provide an improved seal.

In an aspect, there is provided a sealing gasket for a vacuum pump. The sealing gasket comprises: a first sealing member defining a closed shape (e.g. a loop such as an annulus or a rounded square) and comprising: a first surface; a second surface opposite the first surface; a first inner surface (which may be a radially inner surface); and a first outer surface (which may be a radially outer surface) opposite to the first inner surface, wherein the first inner surface and the first outer surface are disposed between the first surface and the second surface; a second sealing member defining a closed shape and comprising: a third surface; a fourth surface opposite the third surface; a second inner surface (which may be a radially inner surface); and a second outer surface (which may be a radially outer surface) opposite to the second inner surface, wherein the second inner surface and the second outer surface are disposed between the third surface and the fourth surface; a first longitudinal sealing member connected between the first outer surface and the second outer surface; and a second longitudinal sealing member connected between the first outer surface and the second outer surface.

The sealing gasket may further comprise one or more curved surface portions and/or one or more planar surface portions disposed between one or more of the first or second sealing members and one or more of the longitudinal sealing members, each of the one or more curved surface portions and/or the one or more planar surface portions being located at an interface between the one or more of the first or second sealing members and the one or more longitudinal sealing members.

The sealing gasket may further comprise one or more curved surface portions and/or one or more planar surface portions disposed between one or more of the outer surfaces and one or more of the longitudinal sealing members, and located at interfaces between the one or more outer surfaces and the one or more longitudinal sealing members.

The sealing gasket may further comprise, at an interface between an outer surface and the longitudinal sealing member connected thereto, a continuous curved surface portion arranged to provide a smooth continuous transition between the outer surface and the longitudinal sealing member connected thereto.

The sealing gasket may further comprise, at an interface between a outer surface and the longitudinal sealing member connected thereto, a curved surface portion and a discontinuity, the curved surface portion and the discontinuity being disposed between the outer surface and the longitudinal sealing member connected thereto.

The sealing gasket may further comprise, at an interface between a outer surface and the longitudinal sealing member connected thereto, one or more discrete planar surface portions disposed between the outer surface and the longitudinal sealing member connected thereto. In some aspects, there may be only one discrete planar surface portion (e.g. a chamfer) disposed between the outer surface and the longitudinal sealing member connected thereto. In some aspects, there may be multiple discrete planar surface portions (i.e. a multi-faceted portion) disposed between the outer surface and the longitudinal sealing member connected thereto.

In a further aspect, there is provided a sealing gasket for a vacuum pump. The sealing gasket comprises: a first sealing member defining a closed shape; a second sealing member defining a closed shape; a first longitudinal sealing member connected between the first sealing member and the second sealing member; a second longitudinal sealing member connected between the first sealing member and the sealing member; and one or more curved surface portions and/or one or more planar surface portions disposed between one or more of the sealing members and one or more of the longitudinal sealing members, and located at one or more interfaces between the one or more sealing members and the one or more longitudinal sealing members.

The sealing may comprise, at an interface between a first or second sealing member and a longitudinal sealing member connected thereto, a continuous curved surface portion arranged to provide a smooth continuous transition between the first or second sealing member and a longitudinal sealing member connected thereto.

In any of the preceding aspects, the sealing gasket may be a one-piece gasket. The sealing gasket may be a moulded gasket. Some or all of the sealing gasket may have square or rectangular cross-section. The sealing gasket may be deformable. The sealing gasket may be made of or comprise an elastomer.

In any of the preceding aspects, the closed shape may be, for example, an annulus, a loop, a ring, or a rounded square (i.e. a square with rounded corners, e.g. substantially a squircle), or a rounded rectangle.

In any of the preceding aspects, the first sealing member may define a rounded square, i.e. a square with rounded corners, e.g. substantially a squircle. The first surface may be a rounded square shaped surface. The second surface may be a rounded square shaped surface. The first sealing member may comprise a first curved section, a second curved section, a third curved section, a fourth curved section, a first substantially straight section disposed between the first curved section and the second curved section, a second substantially straight section disposed between the second curved section and the third curved section, a third substantially straight section disposed between the third curved section and the fourth curved section, and a fourth substantially straight section disposed between the fourth curved section and the first curved section. The first longitudinal sealing member may be connected to the first curved section. The second longitudinal sealing member may be connected to the third curved section.

In any of the preceding aspects, the second sealing member may define a rounded square, i.e. a square with rounded corners, e.g. substantially a squircle. The third surface may be a rounded square shaped surface. The fourth surface may be a rounded square shaped surface. The second sealing member may comprise a fifth curved section, a sixth curved section, a seventh curved section, an eighth curved section, a fifth substantially straight section disposed between the fifth curved section and the sixth curved section, a sixth substantially straight section disposed between the sixth curved section and the seventh curved section, a seventh substantially straight section disposed between the seventh curved section and the eighth curved section, and an eighth substantially straight section disposed between the eighth curved section and the fifth curved section. The first longitudinal sealing member may be connected to the fifth curved section. The second longitudinal sealing member may be connected to the seventh curved section.

In any of the above aspects, the first sealing member may be an annular sealing member. In any of the above aspects, the first surface may be an annular surface. In any of the above aspects, the second surface may be an annular surface.

In any of the above aspects, the second sealing member may be an annular sealing member. In any of the above aspects, the third surface may be an annular surface. In any of the above aspects, the fourth surface may be an annular surface.

In a further aspect, there is provided a vacuum pump, comprising: shell stators defining at least one pumping chamber; end pieces mountable at either end of the shell stator; and the sealing gasket of any preceding aspect.

The sealing gasket may be disposed in one or more seal grooves formed in one or more of the shell stators and/or one or more of the end pieces.

The first sealing member may be disposed in a first seal groove. The first seal groove may define a closed shape selected from the group of closed shapes consisting of an annulus, a circle, an oval, an ellipse, a stadium, a rounded square, a rounded rectangle, a rounded polygon, and a squircle. The first seal groove may be defined in end portions of the shell stators, and/or an end piece. The first curved section may be disposed in a first substantially straight portion of the first seal groove. The second curved section may be disposed in a second substantially straight portion of the first seal groove. The third curved section may be disposed in a third substantially straight portion of the first seal groove. The fourth curved section may be disposed in a fourth substantially straight portion of the first seal groove. The first substantially straight section may be disposed in a first curved portion of the first seal groove. The second substantially straight section may be disposed in a second curved portion of the first seal groove. The third substantially straight section may be disposed in a third curved portion of the first seal groove. The fourth substantially straight section may be disposed in a fourth curved portion of the first seal groove.

The second sealing member may be disposed in a second seal groove. The second seal groove may define a closed shape selected from the group of closed shapes consisting of an annulus, a circle, an oval, an ellipse, a stadium, a rounded square, a rounded rectangle, a rounded polygon, and a squircle. The second seal groove may be defined in end portions of the shell stators, and/or an end piece. The fifth curved section may be disposed in a first substantially straight portion of the second seal groove. The sixth curved section may be disposed in a second substantially straight portion of the second seal groove. The seventh curved section may be disposed in a third substantially straight portion of the second seal groove. The eighth curved section may be disposed in a fourth substantially straight portion of the second seal groove. The fifth substantially straight section may be disposed in a first curved portion of the second seal groove. The sixth substantially straight section may be disposed in a second curved portion of the second seal groove. The seventh substantially straight section may be disposed in a third curved portion of the second seal groove. The eighth substantially straight section may be disposed in a fourth curved portion of the second seal groove.

In a further aspect, there is provided a shell stator for a vacuum pump, The shell stator comprises: a first sealing groove disposed along a joining surface of the shell stator, the joining surface being for receiving a further shell stator thereby to define at least one pumping chamber; and a second sealing groove disposed in an end surface of the shell stator, the end surface being for receiving an end piece; wherein the first and second sealing grooves are connected at an edge of the shell stator via a transitional groove portion that comprises one or more curved surface portions and/or one or more planar surface portions.

The first and second sealing grooves may be connected at the edge of the shell stator via a multi-faceted transitional groove portion comprising multiple planar surface portions.

The first and second sealing grooves may be connected at the edge of the shell stator via a chamfered transitional groove portion comprising only a single planar surface portion.

The first and second sealing grooves may be connected at the edge of the shell stator via a continuous transitional groove portion comprising only a continuous curved surface portion.

The first and second sealing grooves may be connected at the edge of the shell stator via a transitional groove portion comprising a curved surface portion and a discontinuity. The discontinuity may be disposed between the curved surface portion and either the first or second sealing groove.

The first and second sealing grooves may be connected at the edge of the shell stator via a transitional groove portion comprising a curved surface portion and a planar surface portion. The planar surface portion may be disposed between the curved surface portion and either the first or second sealing groove.

The first and second sealing grooves may be connected at the edge of the shell stator via a transitional groove portion comprising a curved surface portion and two planar surface portions. Each planar surface portion may be disposed between the curved surface portion and a respective one of the first and second sealing grooves.

In a further aspect, there is provided a shell stator for a vacuum pump. The shell stator comprises: a joining surface of the shell stator, the joining surface being for receiving a further shell stator thereby to define at least one pumping chamber; a sealing groove disposed in an end surface of the shell stator, the end surface being for receiving an end piece; and a transitional groove portion disposed between the joining surface and the sealing groove at an edge of the shell stator, the transitional groove portion comprising one or more curved surface portions and/or one or more planar surface portions.

The transitional groove portion may be a multi-faceted transitional groove portion comprising multiple planar surface portions.

The transitional groove portion may be a chamfered transitional groove portion comprising only a single planar surface portion.

The transitional groove portion may be a continuous transitional groove portion comprising only a continuous curved surface portion.

The transitional groove portion may comprise a curved surface portion and a discontinuity. The discontinuity may be disposed between the curved surface portion and either the sealing groove or the joining surface.

The transitional groove portion may comprise a curved surface portion and a planar surface portion. The planar surface portion may be disposed between the curved surface portion and either the sealing groove or the joining surface.

The transitional groove portion may comprise a curved surface portion and two planar surface portions. Each planar surface portion may be disposed between the curved surface portion and a respective one of the sealing groove and the joining surface.

In a further aspect, there is provided a vacuum pump comprising: shell stators defining at least one pumping chamber; end pieces mountable at either end of the shell stator; and a sealing gasket disposed between the shell stators and the end pieces. One or more of the shell stators is a shell stator according to any of the preceding aspects. For example, both of the shell stators may be in accordance with one of the proceeding aspects, e.g., different aspects. The sealing gasket may be in accordance with any of the preceding aspects.

is a schematic illustration (not to scale) showing a housingof a vacuum pump, according to one example. The housingcomprises a pair of shell stators,and a pair of end plates,. The shell stators,define recesses which receive components of the vacuum pump. The shell stators,are brought together to retain the components in those recesses. The end plates,are then brought to retain the shell stators,. This provides for particularly convenient assembly of the vacuum pump.

In other words, the housingof the vacuum pump may be formed from multiple component parts, including shells,and end plates,which may be sealed upon assembly. In the arrangement shown in, the stator is formed by bringing together the two housing parts or shells,which are then retained between the pair of end plates,.

As will be explained in more detail below, in this example, to adequately seal the shell stators,together, one or more (e.g. two) longitudinal seals are located along the joining faces of the shell stators,. Also, to ensure adequate sealing between the shell stators,and the respective end plates,, a pair of annular seals is located between the end plates,and the shell stators,.

is a schematic illustration (not to scale) of a sealing gasketfor sealing the housing, according to one example.

The sealing gasketcomprises a first approximately annular sealing member, a second approximately annular sealing member, a first longitudinal sealing member, and a second longitudinal sealing member.

The first annular sealing membercomprises a first annular surface, a second annular surfaceopposite the first annular surface, a first radially inner surface, and a first radially outer surfaceopposite to the first radially inner surface. The first radially inner surfaceand the first radially outer surfaceare disposed between the first annular surfaceand the second annular surface.

The second annular sealing membercomprises a third annular surface, a fourth annular surfaceopposite the third annular surface, a second radially inner surface, a second radially outer surfaceopposite to the second radially inner surface. The second radially inner surfaceand the second radially outer surfaceare disposed between the third annular surfaceand the fourth annular surface.

The first longitudinal sealing memberis connected or attached between the first radially outer surface(of the first annular sealing member) and the second radially outer surface(of the second annular sealing member).

The second longitudinal sealing memberis connected or attached between the first radially outer surface(of the first annular sealing member) and the second radially outer surface(of the second annular sealing member).

The second longitudinal sealing memberis arranged opposite to the first longitudinal sealing member. That is to say, the second longitudinal sealing memberis connected to the first and second annular sealing members,and at an opposite side of the first and second annular sealing members,to the side at which the first longitudinal sealing memberis connected to the first and second annular sealing members,.

The first annular seal memberis a ring-shaped sealing member. The first annular seal memberhas a square or rectangular cross-section.

The second annular seal memberis a ring-shaped sealing member. The second annular seal memberhas a square or rectangular cross-section.

The first longitudinal sealing membermay be an O-ring cord. The first longitudinal sealing memberhas a square or rectangular cross-section.

The second longitudinal sealing membermay be an O-ring cord. The second longitudinal sealing memberhas a square or rectangular cross-section.